Portal Pro is a set of test chambers focusing on solving puzzles locally rather than using complex fling techniques. The goal here is that the solutions are hard to come up with but easy to actually do.
This file will let you run Portal Pro after updating to the SteamPipe version of Portal. If you have not updated Portal, you do not need this patch. Thanks to THEJackinator/Technogeek1994 for providing the file. Installation instructions are below.